Why do I have an underpayment penalty fee in the summary ( before submitting return) yet when I search for why I have a penalty fee, Turbo states I don’t have a penalty?

As a single parent (no other adult help) the Fee of $274 is a lot of money to me. If I legitimately owe it, I will pay it. But I should know why and how to make sure it doesn’t happen again. Thank you!